Too Much Vitamin D?

Q: I recently had some labs done and the dr. told me to start taking 50 mg of zinc an 5000 of vitamin D. That just seemed like a lot of vit D to me. Has anyone else had to take that much before?

The answer to this question is: “It depends on who you listen to.”

Just about everybody knows the sun in about the best source of Vitamin D there is. Problem is, even in sunny climates, most people don’t get enough exposure to the sun (thanks to not being active and/or use of sunscreens all the time) and are deficient in Vitamin D to some degree. Toss in the long winter’s that we experience in the Northern part of the country and odds are likely that you should be taking a Vitamin D supplement.

Vitamin D is processed by both the liver and kidneys and helps in absorbing calcium and works with it to help build and strengthen bones. It also helps with overall cell growth, immune functions and helps regulate glucose tolerance and blood pressure.

The Recommend Daily Intake (RDI) in the US for Vitamin D for the average adult is about 600iu a day (800 for those over 70), but there are many folks that feel this is on the low side, falling in to the “drop in the bucket” category.

According to the Vitamin D Council, 20-30 minutes of exposure to summer sun and your body can produce 10,000iu of Vitamin D. More than 10 times the RDI and twice what your doctor is suggesting you take.

Dietary sources of Vitamin D primarily come from fortified food products (mostly dairy), but “fatty” fish such as tuna and salmon are also great sources. If you are an otherwise healthy adult and get about 10-15 minutes of sunlight exposure a day, and eat salmon or tuna say once a week, you likely won’t need a supplement.

But as colder months close in, you can’t get the sun exposure and so you likely won’t get enough Vitamin D through your diet. Anyone north of about Georgia should look at taking a supplement from about October through April, maybe even including September and May for those in the more Northern areas. Also keep in mind, those with darker skin or those who regularly use sun screens won’t absorb Vitamin D from the sun as easily, so year-round supplementation may not be a bad thing.

How much to take? Based on various research findings, the Vitamin D Council recommends that otherwise healthy adults supplement with 5,000iu daily, so again, you are well within any sort of safe range.

However, I wouldn’t hesitate to ask your doctor when he plans on rechecking your levels again so you can see if your levels are going up.

Vitamin D toxicity is rare, but liver or kidney issues can increase the risk. Some signs of Vitamin D toxicity include nausea, vomiting, muscle weakness, poor appetite and constipation. If you start experiencing any of these symptoms you should contact your doctor.

When choosing a Vitamin D supplement, look for one that uses D3 (cholecalciferol) versus D2 (ergocalciferol). D3 is the form made and used by your body, while D2 is the form you get from plant sources and requires conversion to D3 by the body in order to make use of it. It takes between 3 and 10 unites of D2 to make a unit of D3.

While I think the recommended dosage is on the light side, there is a great info-graphic about Vitamin D over at Information is Beautiful that I think is worth checking out.

Oh, there does seem to be some correlation between low levels of Vitamin D and Zinc, which may be why he’s having you take that as well.